Many telephone systems have a computer data port which is used to provide information relating to the usage of the telephone system. Most PBXs or key telephone systems have an RS-232 serial port through which are output records of the details of each telephone call which occurred on the telephone system. These call detail records may be collected in a computer system and evaluated to determine telephone usage, make price estimations for telephone usage, provide a means to independently verify a telephone billing, and provide reports of telephone usage so as to enable better management of the telephone system, and many other uses.
A mobile cellular telephone does not have a computer data port from which such call detail records can be collected. The cellular telephone company can provide, on a monthly basis, a detailed accounting of the telephone usage. However, the user of the mobile cellular telephone is not able to independently verify the usage of the cellular telephone or perform other analysis of the usage of the cellular telephone as can be done with conventional PBX and key telephone systems.
When a rental car is equipped with a cellular telephone, cellular telephone usage may need to be determined in order for the rental agency to accurately bill the rental customer for the usage of the cellular telephone. It is .inconvenient and impractical for the rental agency to wait for the end of the month to receive the cellular telephone usage report from the cellular telephone company, and then from that report charge the rental customer for the usage of the cellular telephone. The cellular telephone usage must be able to be known quickly and accurately so that the rental agency can correctly charge the rental customer for the usage of the cellular telephone. If a cellular telephone by itself is rented, then usage of the cellular telephone may also need to be monitored so that proper rental rates can be calculated by the rental aqency.
Cellular telephones exist which have an adaptor which converts the cellular telephone handset output from the cellular transceiver into a simulated telephone line which is compatible with common public switched telephone network compatible equipment. Although this adaptor allows commonly available telephone equipment to be connected to the cellular telephone, it does not provide a computer data port which generates call detail records so that the usage of the cellular telephone can be monitored. A practical means of monitoring the usage of a mobile cellular telephone and providing information relating to the usage of the cellular telephone is needed.
Since a cellular telephone has airtime charges which are incurred whenever the telephone is used, both for outbound and incoming calls, the usage of the cellular telephone for both incoming and outbound calls must be monitored. A system to monitor cellular telephone usage must record the date and time of the start of any telephone call, either incoming to the cellular telephone or outbound from the cellular telephone, the duration of the telephone call, an indication that a particular call was incoming or outbound, and any digits which were dialed to place an outbound cellular telephone call. This information is needed in order to accurately monitor cellular telephone usage. In the case of a telephone which is rented and for which a billing must be created based upon usage of the cellular telephone, the bill for the rental customer can be calculated based upon this information. This information must also be known if a printout or computer record which provides a record of the cellular telephone usage is to be created.
A practical means of monitoring cellular telephone usage is needed in order to provide a means by which the usage of the cellular telephone can quickly and easily be determined, so that evaluation or billing based upon the usage of the cellular telephone can practically be accomplished.